1. Field of the Invention
The present invention relates generally to a clamp for use in plugging holes drilled in bone and, in particular, to a cranial clamp which is utilized to cover a burr hole drilled into a skull.
2. Description of the Related Art
In traditional neurosurgery, large sections of bone are removed from the skull. Once the procedure has been performed, there is a need to anchor the bone section back into place. Several mechanisms for achieving this function have been used, including small metallic plates affixed with screws or wires. Another mechanism has been a rigid cranial clamp which consists of two connected circular plates residing on the inside and outside surfaces of the skull.
More recently, neurosurgeons have been performing operations with a small drilled opening in the skull known as a burr hole. Such operations are less invasive than larger craniotomy procedures where larger sections of bone are removed. It is a goal of the neurosurgeon to plug the burr hole following such a procedure, typically utilizing a metallic circular plate affixed with multiple small screws as demonstrated in U.S. Pat. No. 5,578,036 to Stone et al. and U.S. Pat. No. 5,916,200 to Eppley et al.
Cranial clamps are considered superior to the metallic plates in that they are faster to place, do not involve additional drilling of screw holes into the skull, and do not require downward forces onto the skull with a screwdriver. Exemplary cranial clamps in the art include U.S. Pat. No. 6,685,707 to Roman et al., U.S. Pat. No. 6,379,363 to Herrington et al., and U.S. Pat. No. 6,068,631 to Lerch. While each of these cranial clamps are able to perform the intended function, they do not have the ability to be placed through a burr hole having a diameter smaller than the clamp itself. Such prior art clamps generally require additional devices to assist in placing the clamp in position, which further complicates the procedure.
Thus, it would be desirable for a clamp to be developed for use in plugging a burr hole formed in bone, and particularly a skull, which has the ability to be inserted through such burr hole. It would also be desirable for such clamp to be designed so that it is held rigidly in place without a threaded connection.